Effect of soft-segment CH2/O ratio on morphology and properties of a series of polyurethane elastomers

Darren J. Martin, Gordon F. Meijs, Gordon M. Renwick, Pathiraja A. Gunatillake, Simon J. McCarthy

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123 Scopus citations

Abstract

A series of six thermoplastic polyurethane elastomers were synthesized from a 4,4′-methylene diphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender, with polyethylene oxide) (PEO), poly(tetramethylene oxide) (PTMO), poly(hexamethylene oxide) (PHMO), poly(octamethylene oxide) (POMO), poly(decamethylene oxide) (PDMO), and poly(1,6-hexyl carbonate)diol (PCDO) macrodiol soft segments. The soft-segment molecular weights employed were similar (approximately 1000 g/mol) and each polyurethane contained 55% (w/w) of the soft-segment macrodiol. Differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), wide-angle X-ray diffraction (WAXD), and Fourier transform infrared spectroscopy (FTIR) techniques were employed to characterize the morphology. Tensile and Shore hardness tests were also performed. Materials were tested in the as-molded, solvent-cast, and annealed states. It was found that the polyurethanes produced from macrodiols with the highest CH2/O ratio displayed greater hard-domain crystallinity, a higher degree of phase separation, and the greatest hardness, stiffness, and opacity. POMO- and PDMO-based polymers displayed evidence of paracrystallinity in the soft domains. The PCDO-based material displayed a higher degree of phase mixing compared to the polyether-based materials. Annealing increased hard-domain crystallinity in all the polyether-based materials. The solvent-cast POMO- and PDMO-based materials had poor mechanical properties and were difficult to cast. The materials containing macrodiols with the lowest CH2/O ratio were more readily solvent-cast and produced strong, useful films. Morphologies of the solvent-cast materials differed greatly from those of the molded materials.

Original languageEnglish (US)
Pages (from-to)557-571
Number of pages15
JournalJournal of Applied Polymer Science
Volume60
Issue number4
DOIs
StatePublished - Apr 25 1996

ASJC Scopus subject areas

  • Chemistry(all)
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Materials Chemistry

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